Your Gut in Space

Finding the Right Balance for the Microbiota

Trillions of microorganisms live on and in the human body, many of them essential to its function and health. These organisms, collectively known as the microbiota, outnumber cells in the body by at least five times.

Microorganisms in the intestinal tract, the gut microbiota, play an especially important role in human health. An investigation on the International Space Station, Rodent Research-7 (RR-7), studies how the gut microbiota changes in response to spaceflight, and how that change in turn affects the immune system, metabolic system, and circadian or daily rhythms.

Research shows that the microbiota in the mammalian digestive tract has a major impact on an individual’s physiology and behavior. In humans, disruption of microbial communities has been linked to multiple health problems affecting intestinal, immune, mental and metabolic systems.

The investigation compares two different genetic strains of mice and two different durations of spaceflight. Twenty mice, ten of each strain, launch to the space station, and another 20 remain on the ground in identical conditions (except, of course, for the absence of gravity). Mice are a model organism that often serves as a scientific stand-in for other mammals and humans.

Fecal material collected from the mice every two weeks will be examined for changes in the gut microbiota. Researchers plan to analyze fecal and tissue samples after 30 and 90 days of flight to compare the effects of different durations of time in space.

With a better understanding of relationships between changes such as disruption in sleep and an imbalance of microbial populations, researchers can identify specific factors that contribute to changes in the microbiota. Further studies then can determine proactive measures and countermeasures to protect astronaut health during long-term missions.